Every once in a while, the McRib sandwich appears at McDonalds for a few weeks only to disappear again, often for years at a time. Why does this sandwich come and go so sporadically? I think I may have discovered the answer.
Earlier today, my buddy at work relayed a conversation he had with an acquaintance of his who happened to be a farmer. Evidently, the reason the McRib appears only once-in-a-while, and for such a short time, is that every now and then the price of pork goes really low. When this happens, McDonalds buys a whole bunch and turns them into delicious McRibs. This, in turn, leads to a rise in pork prices which reduces the profitability of the McRib sandwich. McDonalds stops buying pork, and the McRib sandwich disappears.
A month ago the McRib sandwich appeared at local McDonalds restaurants (t has since disappeared). This has apparently coincided with an overpopulation in western Canadian sow herds (excess supply = low prices).